Set TAU_MAKEFILE env variable (#2210)

* In order to use TAU module, we have to set TAU_MAKEFILE env variable.

* updated with suggestions from @citibeth

var/spack/repos/builtin/packages/tau/package.py

@@ -24,7 +24,7 @@
 ##############################################################################
 from spack import *
 import os
-import os.path
+import glob
 from llnl.util.filesystem import join_path
 
 
@@ -146,3 +146,8 @@ def link_tau_arch_dirs(self):
                 dest = join_path(self.prefix, d)
                 if os.path.isdir(src) and not os.path.exists(dest):
                     os.symlink(join_path(subdir, d), dest)
+
+    def setup_environment(self, spack_env, run_env):
+        pattern = join_path(self.prefix.lib, 'Makefile.*')
+        files = glob.glob(pattern)
+        run_env.set('TAU_MAKEFILE', files[0])